19-0314; Rev. 0; 10/94 MAX747 Evaluation Kit The MAX747 evaluation kit (EV kit) provides a regulated 5.0V output voltage from a 6V to 15V input. It delivers a 1.25A output current and up to 95% efficiency from a 6V supply using small, surface-mount components. ___________________________Features ♦ 6.0V to 15.0V Input Voltage Range ♦ Fixed 5V or Optional Adjustable Output Voltage ♦ 1.25A Output Current Capability ♦ Up to 95% Efficiency ♦ PWM Architecture ♦ External Shutdown Control ♦ Fully Assembled and Tested ______________Ordering Information PART MAX747EVKIT-SO ____________________Component List TEMP. RANGE BOARD TYPE DESIGNATION QTY 0°C to +70°C Surface Mount C3, C4 2 0.1µF ceramic capacitors C5 1 0.22µF ceramic capacitor C6 1 470pF ceramic capacitor 2 220µF, 10V, low-ESR tantalum capacitors AVX TPSE227M010R0100 or Sprague 595D227X0010R2T 2 68µF, 20V, low-ESR tantalum capacitors AVX TPSE686M020R0150 or Sprague 595D686X0020R2T D1 1 3A, 20V Schottky diode (SMT) Nihon NSQ03A02, Motorola MBRS340T3 or IR30BQ040 L1 1 33µH, 1.8A inductor (SMT) Sumida CDR125-330, CoilCraft D03316-333 P1 1 P-channel MOSFET (SO-8) Motorola MMSF3P02HD, Siliconix Si9430DY or IRF7204 R6 1 0.068Ω, 5% resistor (SMT) Dale WSL-2010-R068-J or IRC LR2010-05-R068-J U1 1 MAX747CSD JU1 1 3-pin header None 1 Shunt None 1 MAX747 data sheet C1, C8 ______________________________EV Kit C2, C7 DESCRIPTION ________________________________________________________________ Maxim Integrated Products Call toll free 1-800-998-8800 for free samples or literature. 1 Evaluates: MAX747 _______________General Description Evaluates: MAX747 MAX747 Evaluation Kit ______________Component Suppliers _______________Detailed Description Jumper Selection SUPPLIER PHONE FAX (207) 282-5111 (800) 282-4975 (714) 969-2491 (814) 237-1431 (800) 831-9172 (603) 224-1961 (207) 283-1941 Capacitors AVX Matsuo Murata Erie Sprague (714) 960-6492 (814) 238-0490 (603) 224-1430 Inductors CoilCraft Coiltronics Sumida (708) 639-6400 (407) 241-7876 (708) 956-0666 (708) 639-1469 (407) 241-9339 (708) 956-0702 Diodes Central Semiconductor Motorola Nihon (516) 435-1110 (516) 435-1824 (602) 244-5303 (805) 867-2555 (602) 244-4015 (805) 867-2556 (310) 322-3331 (602) 244-3576 (408) 988-8000 (310) 322-3332 (602) 244-4015 (408) 970-3950 (402) 564-3131 (512) 992-7900 (402) 563-1841 (512) 992-3377 Power MOSFETs IR Motorola Siliconix Resistors Dale-Vishay IRC _________________________Quick Start The MAX747 EV kit is fully assembled and tested. Follow these steps to verify board operation. Do not turn on the power supply until all connections are completed. 1) Connect a 6V to 15V power supply to the pad marked VIN. Connect ground to the GND pad. 2) Connect a voltmeter and load (if any) to the VOUT pad. 3) Place the shunt across pins 1 and 2 of JU1 for normal operation. 4) Turn on the power supply and verify that the output voltage is 5V. 2 The MAX747 has a TTL/CMOS-logic level input pin (SHDN) to disable the output. Table 1 lists the options for the shutdown control jumper, JU1. An external signal may be used by removing the JU1 shunt and connecting the control signal to the SHDN pad. Table 1. Jumper JU1 Functions SHUNT LOCATION SHDN PIN MAX747 OUTPUT 1&2 Connected to GND MAX747 Enabled, VOUT = 5V 2&3 Connected to VIN Shutdown Mode, VOUT = 0V Setting the Output Voltage The MAX747’s output voltage can be set to 5V by grounding FB, or it can be adjusted from 2V to 14V using an external voltage divider. Resistors R4 and R5, located on the solder side of the PC board, form a voltage divider between the output voltage and the FB pin. Select a value between 10kΩ and 1MΩ for resistor R4. Calculate R5 as follows: VOUT -1 R5 = (R4) ––––––– 2V ( ) Resistor R4 is shorted for a fixed 5V output. Be sure to cut the shorting trace between the pads of R4 before installing the resistor. Also, the shorting trace at JU2 must be cut to disconnect the OUT pin from the output. In adjustable mode, the FB pin becomes the compensation input pin (instead of the CC pin). Remove the CC pin capacitor (C6) and install an FB pin compensation capacitor (C9). Refer to the Compensation Capacitor section of the MAX747 data sheet for instructions on selecting an appropriate capacitor value. The supplied output capacitors are rated at 10V; use a higher rated capacitor if necessary. Using the Low-Battery Indicator The MAX747 has an additional comparator that is useful for monitoring the voltage level of the input source. _______________________________________________________________________________________ MAX747 Evaluation Kit Evaluates: MAX747 VIN C2 68µF 20V C3 0.1µF C7 68µF 20V 3 SHDN LBI 2 JU1 1 R3 OPEN R2 OPEN LBO 4 12 14 1 SHDN AV+ V+ LBO R6 0.068Ω LBI R1 0Ω CS C4 0.1µF 2 7 SS MAX747 EXT 9 11 P1 L1 C5 0.22µF 3 C6 470pF 6 10 REF CC AGND GND GND 8 JU2 C1 220µF 10V R5 OPEN FB 13 33µH D1 MBRS340T3 OUT 5 C9 OPEN VOUT C8 220µF 10V R4 0Ω Figure 1. MAX747 EV Kit Schematic Resistor locations R1 and R2, on the solder side of the PC board, are connected as a voltage divider between the LBI pad and the MAX747 LBI pin. Note that a PC board trace across R1 shorts the LBI pin to ground when this function is not used. Cut the trace before installing R1. Also note that the LBI pad is shorted to the VIN pad by another PC board trace. Cut this trace if a voltage other than VIN is to be monitored. Refer to the Setting the LowBattery Detector Voltage section of the MAX747 data sheet for instructions on selecting values for resistors R1 and R2. High Output Current Capability The MAX747 can be configured to deliver higher output currents. Take care to size external components according to higher peak currents. Refer to the Design Procedure section of the MAX747 data sheet for further details. Surface-mount inductors with higher current capability are available from Coiltronics (CTX-03-12384) and CoilCraft (DO3340). When using the LBO output, install a 100kΩ pull-up resistor (R3). LBO is disabled in shutdown mode. _______________________________________________________________________________________ 3 Evaluates: MAX747 MAX747 Evaluation Kit Figure 2. MAX747 EV Kit Component Placement Guide— Component Side Figure 3. MAX747 EV Kit Component Placement Guide— Solder Side Figure 4. MAX747 EV Kit PC Board Layout—Component Side Figure 5. MAX747 EV Kit PC Board Layout—Solder Side Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 4 ___________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 (408) 737-7600 © 1994 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.